1. Field of Invention
This invention relaes to seat belt systems and more particularly the seat belt systems in which the restraining belts are wound up on a single retractor shaft one over the other.
2. Prior Art
In conventional two belts retracting type seat belt systems in which a shoulder restraining belt and a lap restraining belt are wound up on a single retractor shaft one over the other when only one belt, i.e., the shoulder restraining belt, is pulled out, the remaining lap restraining belt is extended at the same time. However, since no pulling force is applied to the lap restraining belt, this belt will sometimes become slack inside the retractor case (as indicated by the broken line A in FIG. 1). When one of the restraining belts becomes slack inside the retractor case there is a danger that this slackened restraining belt will become stuck between the retractor shaft and the case of the retractor mechanism so that extension becomes impossible. Furthermore, there is also a danger that this slackened restraining belt will interfere with the operation of the emergency locking retractor mechanism. In addition to this, there is a further drawback that if the passenger is not careful while using such a system, slack will sometimes be generated in the restraining belts so that it is not sufficient to restrain the passenger, and this restraining condition is extremely dangerous. Furthermore, such slack in the restraining belts may also occur in systems other than the previously described two belts retracting type system.
This invention has been designed to eliminate these conventional technological defects.